MacPacSat is the first software package to be made available that allows a Macintosh computer to communicate via packet radio with the amateur packet satellites currently in operation, using the PACSAT protocols first described by Harold E. Price, NK6K and JeffWard, G0/K8KA. MacPacSat allows the user to request specific files, automatically download files addressed to the user and to upload text and JPEG files over multiple satellite passes. A small editor is built in to facilitate composing and addressing short text messages. Several status windows are available to monitor the progress of directory reception, file frames received and upload progress, as well as general status messages from the satellite. MacPacSat also decodes and displays telemetry from the amateur satellites.